Water resources utilize a part of hydrologic cycle on the Earth and the amount of flux (flow) is relevant rather than the stock. Fresh water with required quality is valuable only when available where and when water demand exists since the unit price of water is inexpensive. Virtual water should be considered for world water resources assessment, and some estimates related to Japan are presented. Future balance of the demand and supply of world water resources is also presented using land surface models associated with Total Runoff Integrating Pathways (TRIP) and country-base statistics in 0.5 degree by 0.5 degree longitude/latitude resolution. Purification and desalinization to produce safe fresh water is of course one of promising technology expected in the era of “water crisis.” However, the necessary amount of drinking water is limited, and further reduction of the cost to produce municipal water should be required for membrane technology to have its popularity.

View full abstract

21st century is called “Water Century”, because water shortage will be big problem at many places in the world. Amount of river water will be much less than water requirement for agriculture, industry and living. Therefore water will be important resource and its efficient use will be necessary.
Water recycle system will be one of potential solutions, and for constructing this system membrane technology will be essential technology.
In this paper conventional system to use water and its problems are reviewed, and then new system to be developed by using various membrane technologies will be proposed. Finally subjects to be developed for construct proposed system will be explained.

View full abstract

While Japan's inherent water resources are relatively abundant, the country is nevertheless faced with a variety of water-related problems. These include local water shortages and insufficient water supplies due to urban redevelopment, as well as multi-level government restrictions on water usage. Membrane technology is considered to be a promising means of solving these problems. In Japan, the application of membrane technology to water supply treatment began in 1991 with the launch of the MAC21 project. At present, water purification using membranes is being performed at a rate of 130, 000 m³/d.
The application of membranes to the reclamation of sewage has been lagging. In this regard, the membrane bioreactor is expected to be an effective technology not only for water reclamation but also for reducing the risk of pathogenic microorganisms and viruses in environmental water supplies.

View full abstract

As often called that the 21^st century is the age of water, various demands for sustainable water resources and effectual use of water have been risen in the world. In response to such demands, membrane technology plays a great roles and many application of membrane technology for achieving effectual use of water have been spread worldwide. Especially seawater desalination, wastewater reclamation, and purification of groundwater are major approaches for effectual use of water resources with membrane technology. In the field of seawater desalination, significant improvements of membranes and membrane process technology developments provided low cost water with enough reliability to seashore societies. Large scale studies for wastewater reclamation with membranes have been carried out in North America, Europe, South West Asian countries. Actually the new approach of the reclamation water to real drinking water started in Singapore and related persons are seriously watching its results. In case of water purification or clarification of groundwater or river surface water, safe and clean water without any fear of pollution or microbes are obtained by membrane technology.

View full abstract

We have made a new rat hepatocyte culture model for a simple and long-term culturing using the method developed by Funatsu et al, of forming a cell aggregate by centrifugation in hollow fibers.
The centrifugation-derived hepatocyte aggregate in hollow fibers formed a hepatocyte organoid after culturing. Ammonia metabolizing and albumin secretion activity were maintained for more than 2 months. CYP enzyme induction was also observed after more than 1 month culture.
These result suggests that this new three-dimensional culture method will provide a simple and convenient long-term culture of rat hepatocytes and will be useful for research of liver functions and new drug developing.

View full abstract